QUALITY CONTROL OF SPATIAL DATA

Before preparing the SLC maps it was first necessary to compile all 28 base maps and convert them to a digital format. The SLC maps were then compiled using these base maps. The maps were input to the accepted error rate of one line width or 0.5 mm. Besides the usual data processing error checks, each map received a visual verification check and was edge matched to the adjoining sheet. All errors and discrepancies were corrected. A base map containing sufficient information for user orientation was also digitized for each of the map sheets. Each of the 28 thematic coverages were examined for their positional accuracy relative to the earth's surface.

Subsequent to the compilation of printed maps, new polygons were added to the digital map coverage, resulting in an updated version. New polygons were added on a number of occasions:

• for cartographic purposes for version 1.0 (due to elongated waterbodies wide enough to require two lines, islands large enough to be delineated within a waterbody and iregular polygons whose boundaries wander in and out along the coverage border).
• to accommodate the addition of Ecoclimatic boundaries compiled for the Soil Carbon Database (version 1.0).
• to accommodate the addition of Ecozone, Ecoregion and Land Resource Area polygons required by the Ecological Statification Study (version 2.0).

Source: updated from Shields et al., 1991
Contact: Peter Schut